The primary objectives of this Phase 4, open label, prospective U.S. surveillance study are to evaluate the health outcomes of Alpha 1-Antitrypsin (AAT)-deficient subjects who are initiating treatment with ARALAST on patient-related outcomes (PRO), i.e., health-related quality of life (HRQoL), healthcare resource utilization (HCRU), and various laboratory analyses to evaluate the safety of long-term administration of ARALAST.